KISSIMMEE, Fla. — Astros left-hander Mike Hampton returned to Houston on Monday after a routine physical turned up a minor irregularity in his heartbeat.

Hampton was to be examined by team physician Dr. Jim Muntz before undergoing a procedure to correct the heartbeat with an electrical current. The Astros hope to have him back in camp Thursday.

"From what I understand, it's not an uncommon condition and it's not an uncommon procedure he's going to go through," general manager Ed Wade said. "Other than travel time back and forth between here and Houston, we don't expect him to miss any time."

The 36-year-old Hampton has had a hard time staying healthy the past four years. He missed most of 2005 with five stints on the disabled list, then was out all of 2006 (elbow surgery) and all of 2007 (torn flexor tendon). He has 141 career victories, but just eight in the past four years.

Astros manager Cecil Cooper said Hampton has thrown the ball well so far in camp. He wasn't scheduled to throw Monday after consecutive days of bullpen sessions, and left camp without speaking to reporters.

The irregularity showed up on a heart test during a physical Saturday after pitchers and catchers reported for camp.

"It didn't seem like it's a major, major issue, but you never know until you actually get it checked out," Cooper said.

Closer Jose Valverde, last year's NL saves leader, went to the hospital Monday because of an inflamed right forearm that was diagnosed as an infection from an apparent insect bite. He was given antibiotics and isn't expected to be sidelined by the injury.

"It was a little bit of concern earlier today. Apparently he's going to be OK," Cooper said. "We did have a couple scares, but it looks like everybody is going to be fine."